Unmount USB Stick

Where /dev/diskN is the one you have found in previous step as per our example it would be "/dev/disk2".

Write ISO to USB

Write the content of the ISO file:

# sudo dd if=/path/to/downloaded.iso of=/dev/rdiskN bs=1m

/dev/rdiskN is the same disk you have found previously, with an r in front. r is for raw disk, as writing to /dev/rdisk2 is much faster than writing to /dev/disk2. You will be prompted for the administrator's password.